1. Field of the Invention
The present invention relates to highly diffusing plastic sheets which are utilized, for example, in the production of lenticular lens sheets of rear projection television.
2. Description of the Prior Art
In the field of recent rear projection television technique, a light source having a small projection pupil utilizing liquid crystal and digital micromirror device (DMD) as the means for displaying projected images has come to be used. In the rear projection television utilizing such a light source having a small projection pupil, the quality of images tends to be deteriorated by scintillation. The scintillation is also called speckle or flicker and is caused when the diffusion of the light from a small light source is insufficient. To prevent the scintillation, it has been considered effective to incorporate a light-diffusing fine particle into a Fresnel lens sheet or a lenticular lens sheet which constitutes the screen of rear projection television. JP-A-55-12980 proposes to minimize the difference between the refractive indices of light-diffusing fine particle and matrix, while increasing the density of light-diffusing fine particle per unit area by reducing its particle size. Japanese Patent No. 2933248 proposes to regulate the hazes of a Fresnel lens sheet and a lenticular lens sheet, a parallel light transmittance and a half angle α within specific ranges. JP-A-10-246916 proposes to uniformly disperse a spherical crystalline high polymer in a transparent resin in an amount of 0.01 to 30% by weight.